Learn Hardcore Polish: Kiedy jestem chory, wolę zostać w domu. - When I am sick, I prefer to stay at home.

Putting kiedy jestem chory first sounds a bit more like giving a condition first: When I’m sick, (then) I prefer…
Putting wolę zostać w domu first sounds more like a statement of preference, then a clarification of when that preference applies.

Why is there a comma after chory?

In Polish, you normally put a comma between a main clause and a subordinate clause introduced by words like kiedy (when), że (that), który (which/who), etc.

Here:

Subordinate clause: Kiedy jestem chory (When I am sick)
Main clause: wolę zostać w domu (I prefer to stay at home)

So the comma is required:
Kiedy jestem chory, wolę zostać w domu.

If you reverse the order, you also use a comma:

Wolę zostać w domu, kiedy jestem chory.

Why is it kiedy and not some other word for “when,” like gdy or jak?

Polish has several ways to say when:

kiedy – very common, neutral in both spoken and written language
gdy – a bit more formal/literary, but also common; interchangeable with kiedy in most cases
jak – colloquial in the sense when/whenever, especially in spoken Polish

In this sentence you can use:

Kiedy jestem chory, wolę zostać w domu.
Gdy jestem chory, wolę zostać w domu.

Using jak here is more spoken/informal and might sound a bit regional or casual:

Jak jestem chory, wolę zostać w domu.

The safest, most standard choice for learners is kiedy.

Where is the word “I”? Why don’t we say Ja jestem chory?

In Polish the subject pronoun (like ja = I, ty = you) is usually omitted, because the verb ending shows the person.

jestem already tells us it is I am.
So Kiedy jestem chory is normally preferred and sounds natural.

You say Ja jestem chory only:

for emphasis (e.g. I am the one who is sick, not him)
in contrast (e.g. On jest zdrowy, a ja jestem chory. – He is healthy, and I am sick.)

So in neutral sentences, leave ja out.

Why is it chory and not something like chora or chorzy?

Chory is an adjective meaning sick/ill. It must agree with the subject in gender and number.

For ja (I), the form depends on the speaker:

If the speaker is a man: jestem chory
If the speaker is a woman: jestem chora

Plural examples:

We (group of only men or mixed group): jesteśmy chorzy
We (group of only women): jesteśmy chore

So the sentence in a female voice would be:

Kiedy jestem chora, wolę zostać w domu. – When I (a woman) am sick, I prefer to stay at home.

What exactly does wolę mean, and how is it different from lubię or preferuję?

Wolę is the 1st person singular of the verb woleć – to prefer.

wolę = I prefer
It is typically followed by an infinitive or a noun:
- Wolę zostać w domu. – I prefer to stay at home.
- Wolę herbatę. – I prefer tea.

Differences:

wolę (from woleć): preference between options, esp. in specific situations
- Kiedy jestem chory, wolę zostać w domu. – When I’m sick, I prefer to stay at home.
lubię (from lubić): to like (general liking, not comparison)
- Lubię zostawać w domu. – I like staying at home.
preferuję (from preferować): also I prefer, but is more formal/learned, often used in more educated or written contexts; here it’s possible but less natural than wolę.

In conversational Polish, wolę is the most natural choice for this sentence.

Why is the verb zostać used, and not something like zostawać or być?

Zostać and zostawać are a perfective–imperfective pair:

zostać – perfective, focuses on the result: to stay (and remain there)
zostawać – imperfective, focuses on the ongoing action/habit: to (be) staying

In this kind of generic, preference sentence, Polish very often uses zostać with verbs like wolać:

Wolę zostać w domu. – I prefer to stay at home.
(very idiomatic; almost a fixed pattern: wolę + perfective infinitive for a single option/action)

You can say wolę zostawać w domu, but:

it sounds more like I prefer the ongoing state/long-term habit of staying at home (instead of going out regularly)
it slightly changes the nuance and is less natural in this simple “when I’m sick” sentence.

Using być (to be) here would not mean “stay”:

wolę być w domu = I prefer to be at home (focus on being, not on the decision to stay).
The typical collocation here is wolę zostać w domu.

What does zostać mean in general? I’ve seen it used as “to become” too.

Zostać has two main meanings:

to stay / remain somewhere
- Zostać w domu – to stay at home
- Zostać w pracy dłużej – to stay at work longer
to become / end up as (some role/status)
- Zostać lekarzem – to become a doctor
- Zostać prezydentem – to become a president

The meaning is determined by the context.
In wolę zostać w domu, it clearly means to stay (stay at home, not become a home).

Why is it w domu and not w dom or w domie?

Dom is a noun meaning house/home. After the preposition w (in), Polish usually uses the locative case to express location.

Declension of dom (singular, most common forms):

Nominative (dictionary form): dom – house/home
Locative: w domu – in/at home

So w domu is:

w
- domu (locative singular) = in/at home

You don’t say:

w dom – wrong case
w domie – this form exists in dialect/old usage but is not standard today; w domu is the correct modern form.

Also note the difference:

w domu – at home (location)
do domu – to home (direction: going home)

In English we say “at home,” but in Polish it’s w domu (“in home”). Is w domu correct here?

Yes, w domu is the normal, idiomatic way to say at home in Polish.

Prepositions don’t always match one-to-one between languages:

English: at home
Polish: w domu (literally: in home)

You almost always use w domu in contexts like:

Jestem w domu. – I’m at home.
Chcę zostać w domu. – I want to stay at home.
Kiedy jestem chory, wolę zostać w domu. – When I’m sick, I prefer to stay at home.

Why is the tense present (jestem chory, wolę) if we’re talking about any time I’m sick in general?

Polish often uses the present tense to express:

habits
general truths
repeated situations

So Kiedy jestem chory, wolę zostać w domu means:

Whenever I am sick (in general), I prefer to stay at home.

This parallels English quite closely, because English also uses present simple in this kind of sentence:

When I am sick, I prefer to stay at home.

If you wanted a specific future situation, you’d still normally use present in the kiedy clause and future in the main clause:

Kiedy będę chory, zostanę w domu. – When I’m sick (that time), I’ll stay at home.

Could I add a word like “then” in the second part, like wtedy? Would that sound natural?

Yes, you can add wtedy (then) for extra clarity or emphasis:

Kiedy jestem chory, wtedy wolę zostać w domu.

Meanings:

Without wtedy: When I’m sick, I prefer to stay at home.
With wtedy: When I’m sick, then I prefer to stay at home. (slightly more emphatic, a bit more spoken/explicit)

It’s optional. The version without wtedy is perfectly natural and probably more common in written Polish.

How do you pronounce chory and domu?

Approximate pronunciation (using English-based hints):

chory: /ˈxɔ.rɨ/
- ch – like a rough h in Loch Ness or German Bach
- o – like short o in off (but shorter)
- ry – Polish r is trilled; y is like the vowel in roses (but more central), not like English ee
domu: /ˈdɔ.mu/
- do – d as in dog
  - o like off
- mu – m as in man
  - u like oo in food

Stress is on the first syllable in both: CHO-ry, DO-mu.